Add metadata server fixture

Create a dedicated metadata server fixture that can be used in tests
that want to bring up a metadata server during functional testing.

This also separates out metadata related variables we were setting up
in the OSAPIFixture for no good reason.

Change-Id: Id4b953634aa74f7736e494eba916fe234cc57fd4

nova/tests/fixtures.py

@@ -435,16 +435,16 @@ class OSAPIFixture(fixtures.Fixture):
         # host, and dynamically allocate ports
         conf_overrides = {
             'osapi_compute_listen': '127.0.0.1',
-            'metadata_listen': '127.0.0.1',
             'osapi_compute_listen_port': 0,
-            'metadata_listen_port': 0,
             'verbose': True,
-            'debug': True
+            'debug': True,
         }
         self.useFixture(ConfPatcher(**conf_overrides))
+
         self.osapi = service.WSGIService("osapi_compute")
         self.osapi.start()
         self.addCleanup(self.osapi.stop)
+
         self.auth_url = 'http://%(host)s:%(port)s/%(api_version)s' % ({
             'host': self.osapi.host, 'port': self.osapi.port,
             'api_version': self.api_version})
@@ -454,6 +454,43 @@ class OSAPIFixture(fixtures.Fixture):
             'admin', 'admin', self.auth_url, self.project_id)
 
 
+class OSMetadataServer(fixtures.Fixture):
+    """Create an OS Metadata API server as a fixture.
+
+    This spawns an OS Metadata API server as a fixture in a new
+    greenthread in the current test.
+
+    TODO(sdague): ideally for testing we'd have something like the
+    test client which acts like requests, but connects any of the
+    interactions needed.
+
+    """
+    def setUp(self):
+        super(OSMetadataServer, self).setUp()
+        # in order to run these in tests we need to bind only to local
+        # host, and dynamically allocate ports
+        conf_overrides = {
+            'metadata_listen': '127.0.0.1',
+            'metadata_listen_port': 0,
+            'verbose': True,
+            'debug': True
+        }
+        self.useFixture(ConfPatcher(**conf_overrides))
+
+        # NOTE(mikal): we don't have root to manipulate iptables, so just
+        # zero that bit out.
+        self.useFixture(fixtures.MonkeyPatch(
+            'nova.network.linux_net.IptablesManager._apply',
+            lambda _: None))
+
+        self.metadata = service.WSGIService("metadata")
+        self.metadata.start()
+        self.addCleanup(self.metadata.stop)
+        self.md_url = "http://%s:%s/" % (
+            conf_overrides['metadata_listen'],
+            self.metadata.port)
+
+
 class PoisonFunctions(fixtures.Fixture):
     """Poison functions so they explode if we touch them.